Everett L. Shock, Ph.D. - US grants

This research project in theoretical organic geochemistry will address problems of critical importance to the understanding of the chemical transformations which organic compounds undergo in geochemical processes. Research objectives include calculation of relative stabilities and activities of organic aqueous species as functions of temperature, pressure, fugacities of various gases (O2, CO2, CH4, NH3, etc.) and activities of inorganic aqueous species, estimation of thermodynamic data and equation of state parameters for organic aqueous species, prediction of pKa values for organic acids and bases at high temperatures and pressures, and estimation of activity coefficients for aqueous species in electrolyte solutions. The focus of this research will be on the conditions of diagenesis with the goals of enhancing understanding of the observed distribution of organic aqueous species in sedimentary basin solutions, identifying plausible chemical reactions between these species, organic matter (kerogen and petroleum) and minerals, and predicting which organic aqueous species should be found in future extended searches of natural solutions. This research requires an interdisciplinary approach combining theoretical equations, thermodynamic data, computer techniques, and field and laboratory observations to achieve these goals.

The growing evidence of hydrothermal processes in layered mafic intrusives (LMI) has brought to the forefront the question of aqueous transport of platinum-group elements (PGE). We propose to pursue an integrated theoretical and petrologic study of PGE mobility in hydrothermal solutions. An internally consistent set of thermodynamic data for aqueous PGE ions and complexes will be developed using recent advances in theoretical geochemistry. These data will be employed in calculations to establish the speciation of PGE in solution, and solubility of platinum-group minerals (PGM) over a large range of geologic conditions. Mass transfer calculations will allow incorporation of petrologic constraints, together with thermodynamic data, in order to identify which factors control PGM dissolution and reprecipitation during hydrothermal events associated with LMI. Petrologic constraints will be drawn from concurrent research on the Duluth Complex in Dr. Pasteris' lab, ongoing research by Dennis Bird on the Skaergaard Intrusive, and literature reports on the Bushveld and Stillwater Complexes. Expected results include: predicted dissociation constants for PGE-complexes of chloride, hydroxide, and other major ligands; predicted solubilities of PGM as functions of temperature, pressure, oxygen fugacity, total chloride, and pH; and increased understanding of the possible role of supercritical aqueous solutions in the redistribution of PGE in LMI and other hydrothermal environments.

The primary goals of this research are an enhanced understanding of how organic compounds respond to aqueous alteration and the relation of this response to the observed distribution of organic compounds in petroleum, oil-field brines, low-grade metamorphic rocks and hydrothermal fluids. These objectives will be met by computing the relative stabilities of organic compounds in coexisting gas, aqueous, petroleum and disseminated phases, and using these calculations to help interpret field, analytical and experimental observations. Relative stabilities will be evaluated from thermodynamic data as functions of temperature, pressure, fugacities of various gases (O2, H2, CO2, CH4, NH3, N2, H2O, etc.), and activities of organic and inorganic aqueous species. Where experimental data are not available, existing estimation methods will be used. In the case of aqueous species, these methods will be enhanced to account for a variety of organic compounds (branched and cycloalkanes, polycyclic aromatics, dicarboxylic acids, sulfur-bearing compounds, etc.) which have not yet received attention, and for which high temperature/pressure data are generally not available. The geologic focus of this research will be conditions at which aqueous solutions interact with organic compounds in petroleum reservoirs, sedimentary rocks, hydrothermal systems and metamorphic terranes. This research requires an interdisciplinary approach combining theoretical equations, thermodynamics and kinetic data, computer techniques and field and laboratory observations to achieve these goals.

This is a theoretical study of: (1) the influence of water-rock interactions on the mineralogic and chemical compositions of the lower oceanic crust and upper an mantle, and (2) an integration of inorganic vent fluid chemistry with hydrothermal alteration of organic matter at sedimented ridges. Once the major rock-forming element chemistry is better understood, linkages between shallow and deep hydrothermal fluids can be elucidated. Trace element and organic compound transport, as well as alteration and redistribution, will be incorporated.

9406211 Shock This award provides one-half the funding required for the acquisition of an inductively-coupled plasma mass spectrometer system to be installed and operated in the Department of Earth and Planetary Sciences at the Washington University in St. Louis. The University is committed to providing the remaining funds necessary to acquire the equipment. The analytical capabilities of the instrument are needed in research and graduate teaching within the University's new program of Environmental Geochemistry and Dynamics, as well as in a wide range of research projects in environmental geochemistry, cosmochemistry, fluid/rock interactions, analysis of sediment deposits by the Missouri and Mississippi floods of 1993, and migration of trace metals from sites of oil field brine contamination. ***

*** 9415558 Shock This three-year award will support U.S.-France cooperative research in geochemistry between Everest L. Shock of Washington University and Vladimir Mayer of the University of Blaise Pascal. The objective of their research is to test models of thermodynamic data with experimental measurements for a wide variety of aqueous inorganic and organic fluids. Minerals, gases, organic compounds, microorganisms and the byproducts of human activity are brought into contact by aqueous fluids in relatively shallow regions of the earth's crust. These fluids facilitate reactions which would otherwise be sluggish. Accurate thermodynamic data for dissolved ions, electrolytes, gases, and organic compounds are needed to develop predictive models. Dr. Shock brings to this collaboration his expertise in theoretical geochemistry. He has developed a model for prediction of thermodynamic data for thousands of aqueous organic and inorganic species. Data are incomplete or wholly lacking at high temperatures. The French investigator, Dr. Mayer, has worked for a number of years in the generation of high temperature measurements for these species. His experimental work will provide the high temperature data that are needed to extend the accuracy and applicability of the existing model. Their joint effort will advance our understanding of sub-surface earth processes and improve current efforts to contain, and eventually avoid environmental problems. ***

9418500 Shock Despite the enormous amount of research that has gone into characterizing the organic composition of geologic fluids, there still remains only a rudimentary understanding of the fundamental reaction pathways and mechanisms by which transformation occur when hot aqueous solutions interact with organic matter in natural processes. The emerging paradigm of metastable equilibrium provides a framework with which the dynamic relationships among organic compounds in geologic fluids such as oilfield brines and hydrothermal solutions is leading to a clearer understanding of the organic transformations responsible for the observed composition of these fluids, and has lead to new ideas about the origin, transport, accumulation and alteration of petroleum. The proposed research seeks to expand our knowledge of metastable equilibrium states, and improve their applicability for understanding geochemical processes. Specific issues to be addressed in the proposed research include: The breadth of metastable equilibrium states. At present, metastable equilibrium arguments are based largely on carboxylic acids in oilfield brines. Which other organic compounds present in natural solutions participate in metastable equilibrium states, and which do not? Do specific families of compounds reach metastable equilibrium, while others do not? The mechanistic implications of metastable equilibrium states. Can the observed metastable equilibrium relationships be used to construe the reaction pathways that actually occur in natural settings? The need for catalysts. Do the inferred pathways require the participation of a catalyst? What catalysts are available in these environments and in what from? To what extent do microorganisms catalyze these reactions? These issues are to be addressed through an approach that coordinates theoretical calculations with sampling and analysis of organic solutes in natural and experimental solutions. This effort will include: 1) collection and analysis of geologic fluids (initially oil-field brines) to achieve a more thorough inventory of their organic composition than is presently available, 2) incorporating these analyses into new tests of metastable equilibrium which will allow us to identify which compounds participate in metastable equilibria, 3) using the results of these calculations, identify the pathways by which organic compounds are transformed in natural settings, 4) comparison of these results with laboratory studies to identify which reaction pathways require catalysis, and 5) initiating the search for likely catalysts.

9714288 Amend PROJECT SUMMARY The isolation and characterization since 1980 of several dozen species of hyperthermophilic microorganisms are largely responsible for the tremendous current interest in life in extreme environments on Earth as well as on other planetary bodies in our solar system. Most known hyperthermophiles were cultured from rock and water samples collected at deep submarine hydrothermal vents or terrestrial hot springs. Although much has been learned about microbial physiologies, phylogenetic diversity, and novel metabolic pathways from this relatively sparse set of organisms, the true extremes of genetic diversity and metabolic strategies on Earth and elsewhere are impossible to predict a priori. This concept is underscored by the widely accepted notion that less than 0.1 percent of all extant microbial species are currently known. Knowledge of microbial species thriving in extreme environments can be expanded through the application of innovative methods to isolate and culture novel species of extremophiles. Like all living organisms, hyperthermophiles are intimately associated with their host environment. Therefore, a detailed understanding of the geochemistry of hydrothermal environments is likely to place constraints on essential substrates for life. To reach this overall goal, this project will combine thermodynamic calculations to determine potential energy sources with detailed chemical analyses of hydrothermal fluids to design new media for growing a wide variety of hyperthermophiles. The readily accessible and chemically diverse hot springs in the Aeolian Islands, Italy, including those on Vulcano, are ideal sampling sites for this highly interdisciplinary study.

This award in the Mars-Rock Special Research Opportunity activity supports theoretical evaluation of mineral alteration in hydrothermal systems by Dr. Everett L. Shock of the Earth and Planetary Science Department, Washington University. The project is funded by the Office of Polar Programs, the Chemistry Division, and the MPS Office of Multidisciplinary Activities. Martian meteorites show isotropic, petrological and mineralogic evidence for hydrothermal or aqueous alteration of the martian crust. The presence of thermaphilic microbes in terrestrial hydrothermal ecosystems raises the possiblity that subsurface life, independent of photochemistry, atmospheric chemistry, and the presence of a surface hydrosphere, may exist or have existed in hydrothermal environments on other planets. In order to develop a predictive model for crustal alteration on Mars, all petrologic, geochemical and isotopic data on minerals and organic compounds in ALH84001 and other martial meteorites will be used to examine various pathways for the formation of carbonate minerals, polycyclic aromatic hydrocarbons, and other organic compounds during water-rock reactions. Rigorous, quantitative models of geochemical mass transfer based on irreversible thermodynamics will be used. The results will determine the constraints on temperatures and fluid compositions required for mineral alteration and organic synthesis. Recent advances in the theoretical geochemistry of hydrothermal systems and ongoing research in geochemical bioenergetics will be used in developing the model. The research will involve conducting theoretical mass-transfer calculations that simulate the reactions of aqueous fluids with a rock of the composition of martian meteorites to establish the ranges of temperature and fluid composition consistent with the deposition of carbonate minerals without the formation of hydrous silicate phases. The conditions leading to carbonate deposition will be compared to those necessary for synthesis of aqueous organic compounds from carbon dioxide. Specific attention will be paid to whether polycyclic aromatic hydrocarbons are compatible with the alteration assemblage at metastable redox equilibrium. The discovery of microbes capable of living in terrestrial hydrothermal conditions raises the possibility that life may have existed in similar conditions on Mars or other planets. A theoretical model that compares geological conditions to the requirements for organic synthesis will be developed. The result will be an analysis of the potential for martian hydrothermal systems to support hydrothermal ecosystems.

Reysenbach/Shock

Studies over the past decade have revealed that life may have penetrated every possible niche where there is an exploitable source of energy. Moreover, life is a major geochemical force which apparently has effects over a wider range of environments than previously appreciated. Extreme environments such as those at high temperature hydrothermal vents offer a good example to the extent to which geochemistry can control or influence the distribution and physiology of microorganisms, and the extent to which the organisms can transform their geochemical environment. An integrated interdisciplinary approach is proposed using a combination of molecular ecological tools, biogeochemical measurements and standard microbiological methods to determine the community and geochemical dynamics in these ecosystems. Specifically, the objective of the study is to establish how deeply branching lineage of the Archea and Bacteria in high temperature ecosystems transform their geochemical environments. Field work will be conducted in Yellowstone National Park. Detailed geochemical and biological analyses along the temperature gradients will provide the framework for addressing specific questions regarding the growth and physiology of the members of the communities. The results of this study will provide a much needed baseline of ecological and geochemical data, and offer quantitative models of the geochemical bioenergetics associated with these high temperature ecosystems. With the elucidation of the key biogeochemical parameters it should be possible to predict the factors that determine the distribution, dynamics, and growth requirements of the deepest lineages within the Archea and Bacteria. Furthermore, this study will challenge our perspective of biogeochemical and microbiological processes, theories on the origins of life and provide predictions about life forms that may exist on other planets.

9807679
Morris
This proposal uses lead smelting in the oak-hickory forests of SE Missouri as a natural laboratory for studying the groundwater mobility, speciation and bioavailability of Pb, Cd, Cu and Zn. The P.I.s' preliminary work shows that the isotope composition of lead washed from leaf surfaces maps the fallout of particulate lead around the smelter. Residual lead from inside plant leaves represents Pb from the soil; initial isotope data and high Pb concentrations inside the leaves strongly suggest that smelter Pb is groundwater soluble, mobile and bioavailable. Thus, the widely recognized ecosystem and human health hazards of particulate Pb may set the stage for more subtle, but more widespread, effects due to mobilization of anthropogenic Pb in groundwater and its biomagnification. The P.I.s propose to address the redistribution and bioavailability of Pb through studies of atmospheric deposition, an ecosystem audit, studies of biological isotope fractionation, and theoretical models of speciation and transport. Undergraduate classes in the Departments of Earth and Planetary Sciences, Chemical Engineering and Biology will participate in field, analytical and theoretical work. High school students will be involved in all phases, through the NSF Young Scholar's Program.

This proposal was part of the Environmental Geochemistry and Biogeochemistry program. It will be jointly funded by the Division of Atmospheric Sciences, Division of Chemistry, Division of Earth Sciences, and by the MPS Office of Multidisciplinary Activities.

0106925
Criss

A new model of solute and isotopic transport in natural waters is being refined and tested. This model can quantiy the timescales of transport without ad hoc assumptions, about ixing groundwater and surface water components. Based on diffusion theory, storm events are treated as "delta functions" that induce a complex series of geochemical and physical responses. The transport equations are readily transformed into linear versions whose intercepts accurately retrodict the timing of the storm events, and whose slopes reveal the time constants for transport of each creochemical constituent. The basic concept is to study the natural system with perturbations provided by natural processes.
Information gained onthe geochemical and isotopic response of surface streams and springs to storm events would determine the timescales of complex natural responses. Data colllected in the first
stage of this project show that different parameters (ionic concentraions, total dissolved organic compounds, nutrients, sediment, oxygen isotopes, etc.) have in a qualitatively similar manner, explicable by the model, but that the timescales vary greatly among the parameters that collectively define the response of the natural system. Rigorous tests of this model will be conducted with
geochemical and isotopic data collected from several sites within an unimpounded river basin (the Meramec Basin, eastem Missouri). This endeavor will be facilitated by an autosampler
installed a karst spring at Washington University's Tyson Research Center, and a new autosampler nearby on the Meramec River. These programmable devices will allow intensive sampling to resolve timescales accurately, and will permit detailed comparisons of simultaneous groundwater and riverine responses to precipitation events. Key questions concerning the sources, the reactions (solubility, ion exchange, adsorption, biological uptake, etc.), the migration paths, and the timescales of pollutant and pathogen transport through surface and near-surface environments will be explored. The new approach appears to be applicable to diverse geochemical, physical, and isotopic constituents. It has the unique potential to resolve the complexity of natural systems using natural events.

The primary goal of the research is to predict the extent and diversity of near-ridge subsurface microbial habitats by constructing thermodynamic and kinetic models of the geochemical interactions between rocks, fluids, and microorganisms in the hydrothermally influenced subseafloor. The geochemistry of ridge axis subseafloor environments will be modeled by calculating the full range of likely fluid compositions and available microbial energy. The work will build on the current state of the art in reaction path and reactive transport models by considering interactions between fluids, rock and microbes, involving a suite of likely crustal compositions, phase-separated fluids, conductivity-cooled fluids, and mixtures of these with seawater and conductively-heated seawater.

This study will test several hypotheses about organic transformations through independent thermodynamic models of reversible and irreversible processes in comples water/mineral/organic systems. The hypotheses to be tested include: (1) The transformation of solid and liquid organic compounds in heated sediments near ridge hydrothermal systems can be interpreted in terms of aqueous alteration, hydrolytic disporportionation, and the approach towar metastable equilibria using models based on irreversible thermodynamics. (2) Marine dissolved organic matter is altered into characteristic suites of simple organic solutes when heated in submarine hydrothermal systems. These compounds are driven toward metastable states at high temperature, but provide support for heterotrophic hyperthermophiles when vent fluids mix with seawater. (3) Owing to coupled electron-transfer processes, there are reaction pathways involving inorganic and organic sulfur compounds that expedite the transformations documented in hydrothermal organic compounes.

AST 0507778
Zolotov

Increasingly, astronomical observations of planets are being used to reveal the active processes within planetary atmospheres and between atmospheres and planetary surfaces. The growing sophistication of photochemical models for atmospheric processes, and calculations of reactive interaction of atmospheres and surfaces, will benefit from additional constraints provided by theoretical models of volcanic gas compositions. On the one hand, new models for volcanic gases are already integral to studies of planetary bodies with active volcanism such as the Jovian satellite Io. On the other hand, theoretical models of volcanic gas compositions will help constrain models of the evolution of atmospheres and surfaces on planets with volcanic histories. The abundances and speciation of volcanic gases reflect the pressure at volcanic vents, temperatures, oxidation states, and compositions of parental magmas, all of which can be used to explore the interiors of volcanically-active planetary bodies.

A program of theoretical geochemical modeling will be led by Dr. Mikhail Zolotov that will lead to testable predictions about the composition and speciation of volcanic degassing and its effect on atmospheres and surfaces of planetary bodies. Bulk compositions of degassed volatiles will be bracketed from cosmochemical, terrestrial volcanological, and experimental data on the solubility of volatiles in magmas. To the greatest extent possible, this study will constrain magma temperature, vent pressures, and the oxidation state of planetary interiors. The work will greatly expand thermodynamic databases so that chemical equilibria in gas-solid systems can be used to model speciation of volcanic gases at the bulk compositions, vent pressures, temperatures and oxidation states of magma determined to be plausible for planetary bodies. The analysis will include speciation in the H-C-O-S-Cl-F-N system. Specific models will be developed for volcanic degassing on Mars, Venus and Mercury, and comparative studies will be performed.

Results of this project will assist other researches who analyze the impact of volcanic degassing on atmospheric and surface chemistry, climatic effects of volcanism, and physics of eruptions, as well as coupled atmosphere-lithosphere evolution on terrestrial planets. An interactive website will be developed for research and education to demonstrate the importance of volcanic degassing on atmospheric, geochemical, geological, and biologic processes on planetary bodies. The website will include a code to compute speciation of volcanic gases at given temperature, pressure, and bulk composition in an interactive mode. Portions of the research will be carried out by a graduate student whose results will be presented at national meetings. Results will also be incorporated into
geochemistry, biogeochemistry and cosmochemistry courses for undergraduate and graduate
students. A public lecture will be given about extraterrestrial volcanism and the role of volcanic
degassing on planets, satellites, and large asteroids.
***

EAR-0520648
Anbar

This proposal will fund an ICP-MS technical specialist to support innovative research in the newly renovated and equipped W.M. Keck Foundation Laboratory for Environmental Biogeochemistry at Arizona State University (ASU). The goal of this laboratory is to promote research at the intersection of the geosciences, the life sciences and chemistry by capitalizing on recent advances in mass spectrometry. The new position will therefore support the development and application of novel analytical methods. A special focus of this position will be new types of isotopic analyses made possible by the development of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Examples of planned work include: the use of Mo isotope measurements in ancient sediments to reconstruct changes in the amount of oxygen in the atmosphere and oceans; the measurement of Fe isotopes to better understand the environmental chemistry of this biologically essential element, and exploration of Cr isotopes to trace toxic pollutants. In addition to supporting specific research projects, this award will enhance the development of a vibrant new program in isotope biogeochemistry at ASU that brings together researchers in several departments, schools, centers and institutes spanning a number of disciplines. The award will make it possible for us to effectively fold our new instruments into integrative graduate and undergraduate training as part of this program. It will also enhance the ability of ASU faculty to mentor post-Ph.D., non-tenure-track staff scientists, several of whom are involved in the planned research efforts.

EAR-0525453/EAR-0525561/EAR-0525500
One of the most profound discoveries emanating from molecular phylogenetic studies is that the "universal tree of life" is exclusively populated in its deepest branches by thermophiles. Two opposing theories about why this might be are:
Life first arose in a hydrothermal environment, possibly in the deep subsurface.
Thermophiles preferentially survived the "late heavy bombardment" of the Hadean Earth.
Since no sedimentary record survives from this period, it is not possible to address these theories directly through geology. Instead, we must look to modern geomicrobial processes to better understand controls on, and modes of, thermophilic life. Armed with this understanding, geological records may eventually yield more information on the physiological capabilities and nature of early life.

This proposal addresses geomicrobial processes at interfaces between mildly reducing hydrothermal fluids and oxidizing surface sediments or waters. Specifically, we will use a combination of molecular, chemical, and isotopic methods to identify the geomicrobial associations, metabolic strategies, nutrient, and energy requirements and geochemical signatures of streamer and biofilm-forming communities (SBC) of thermophilic and chemolithotrophic Bacteria and Archaea.

We will address the following questions:
1) What is the physiochemical basis for the occurrence of biofilm-forming Aquificales?
2) What is their primary carbon source and mode of carbon assimilation?
3) What are the identities of the Crenarchaeota that appear to co-colonize these systems?
4) Is there a co-dependence of these microbes and, if so, what is its basis?
5) Can biosignatures be used to distinguish thermophilic and mesophilic communities?
6) Might these systems leave a molecular record that could be traced back in time?

Scientific Merit: Through this research, we will learn more about the physiological basis for life at high temperatures and the characteristic biosignatures of thermophilic microbes. In particular, we will seek to discern if there is a symbiosis or simply a physical co-habitation of thermophilic Aquificales and Crenarchaea in the SBCs of Yellowstone National Park. These organisms occupy a special niche at the interface of hot, sub-subsurface hydrothermal fluids and a "cold" and oxidizing atmosphere. In seeking to increase understanding of microbes and biogeochemical processes operating at this interface and the strategies used to derive energy and nutrients, our proposal is firmly aligned with the aims and objectives of the Biogeosciences Program. In combining cutting-edge geochemical and microbiological approaches, we will also be generally improving methods and research techniques for the study of geomicrobial processes.

Broader Impacts: This proposal focuses on teaching and training and will support the training of a new postdoctoral investigator and graduate student at MIT and will provide unparalleled research opportunities for undergraduates interested in the biogeosciences, including significant collaborative interactions in the field and laboratory at three institutions. Providing meaningful and positive research experiences in multidisciplinary science to college undergraduates is critical to fostering the next generation of researchers and educators. Because the focal point of our research is one of the US's most visited national parks, there will be enhanced opportunities for public dissemination of our results. We will work directly with the Park Service to develop educational materials, including scientifically sound treatment of the philosophical and practical aspects of fundamental research pertaining to "origins of life" and "limits of life" concepts.

With this award from the Chemistry Research Instrumentation and Facilities: Multi User program (CRIF:MU), the Department of Chemistry at Arizona State University will acquire a multi-purpose powder diffractometer for the X-ray facility. This diffractometer will be used for research and education in the study of (1) semiconductor metal hydrides and in fundamental studies of metal/semimetal-hydrogen interactions and their consequences to chemical structures and physical properties, (2) mechanisms of carbon dioxide mineral sequestration which are important for the development of economically viable low pressure sequestration processes, (3) the study of complicated phase relations and structural chemistry of silicates at the boundary between the Earth?s upper and lower mantle, (4) the role of minerals in the enrichment and distribution of metal trace elements in biofilms, sediments and soils, (5) the synthesis of structure-property relationships of ferromagnetic metals, and (6) nucleation and growth events in glass materials important for a general understanding of the physical chemistry of glasses and for manufacturing ceramics with special properties.

The X-ray diffractometer allows accurate and precise measurements of the three dimensional structure of a molecule, including bond distances and angles, and it provides accurate information about the spatial arrangement of the molecule relative to the neighboring molecules. The synthesis of materials having an extended structure, such as polymers, inorganic solids, glasses, or gels, often yields a polycrystalline or phase-impure powder. Powder X-ray diffraction (Powder XRD) is the most powerful tool available for the structural characterization of such products. Powder XRD pattern can elucidate the structure and relative abundance of the crystalline phases present, it can expose the existence of preferred crystalline orientation (called texture) of a film of a material relative to a crystalline substrate surface, and the XRD linewidth can provide an estimate of the mean crystallite (or grain) diameter. In addition, the structure of extremely thin films (<100 nm) of materials can be investigated by powder-XRD whereas such films cannot be probed by single-crystal XRD. These studies will have an impact in a number of areas, especially synthetic chemistry.

ABSTRACT-0752541 (Shock)
Intellectual Merit: This research provides the theoretical framework and tools needed to model and interpret the increasing evidence for the presence and actions of microbes in the deep biosphere in oceanic crust. It will also allow us to make predictions of microbial habitation and metabolic mechanisms which will ensure greater returns on the costly investments required to access the deep biosphere through seafloor exploration and drilling. This research uses existing data on diffuse fluids and altered rocks from subsurface basalt aquifers to quantify the supply of energy that can be used by microbes.
Work to codify the interactions between essential biomolecules and enzymes and geological materials will permit the prediction of mechanisms of microbial metabolism as function of temperature, pressure, fluid composition, and extent of rock alteration. Justification for the work comes from the fact that the deep biosphere in the oceanic crust is sustained by the disequilibrium between seawater and igneous rocks. Recent work provides estimates of the supply of energy that supports the deep biosphere derived from observations of the extent of oxidative alteration of basalts and other crustal igneous rocks that suggest the portion of the deep biosphere hosted in altering igneous rocks may rival that in seafloor sediments. As a result, the deep biosphere has become a major target for Earth exploration, but lack of knowledge of the signatures of and metabolic needs of microbes in the subsurface have prevented us from adequately investigating their presence and importance. This research attacks this issue.

Broader Impacts: Broader impacts of the work include development of a thermodynamic framework for microbiological processes that will be made publicly available on the Internet. Results of the work also cross over into biology and can be used by environmental scientists for the bioremediation of toxic waste and the downstream impacts of engineered nanoparticles. The work also supports the training of graduate and undergraduate students and the creation of a display for the Arizona State University Open House and Museum on the deep biosphere. Work will complement activities in both NSF's IODP and Ocean Observing Systems Programs.

Intellectual Merit: This research explores how geochemical processes support microbes living deep in the Earth. A major challenge in understanding how life can survive at depth is the identity and source of organic compounds that are consumed by microbes. While some of these compounds are likely to be produced by other subsurface microbes, this works focuses on the large inventory of consumable organic compounds that comes from geochemical transformations of organic matter that take place as sediments are buried and exposed to elevated temperatures and pressures. Goals of the work are to examine, both theoretically and experimentally, chemical reactions that occur at temperatures and pressures greater than microbial life can withstand. These high temperature and pressure reactions produce organic solutes that are transported upward into the inhabited zones of the subsurface. The primary focus of the research is to determine how reactions between hot water and organic matter generate small organic compounds that ultimately feed the deep biosphere. Phase I focuses on hydrothermal experiments of well-known reactions that transform simple hydrocarbons into alcohols, ketones, and carboxylic acids at elevated temperatures and pressures. Phase II explores these same reactions, but in the context of a more realistic and thus complex geologic system that includes the clay minerals found in all organic rich sediments and sedimentary rocks. Most of these reactions have not been systematically studied under geologically realistic conditions. As a result, our present understanding of these transformation mechanisms in nature are speculative. This work produces rigorous results from which calculations can be made to predict the microbial metabolic potential of areas deep within the Earth?s crust.

Broader Impacts: This work provides organic chemists with new methods to control reactions and provides geochemists with new predictive, mechanistic models of organic matter transformations. New models will inform those making site selections for future ocean and continental drilling efforts that explore the deep biosphere and will allow us to better understand the generation of petroleum. This project also provides a means to predict where prospecting of new microbial species with unusual properties can be found. The hydrothermal reactor approach may also provide green alternatives to incineration or burial of organic waste. In terms of education and training, the work supports post-docs, graduate students, and undergraduates, and supports PIs whose gender is under-represented in the sciences. Public outreach will include development new materials for the ?I?m College Bound? program. Graduate and undergraduate researchers associated with this project will help develop new geo/earth science demonstrations and coordinate student volunteers. The demonstrations, assignments and lesson plans will be disseminated and published on the "I'm College Bound" web site.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

Microbial habitats in extreme environments and organic transformations at ridge-crest hydrothermal systems are receiving increased attention as the novel properties of microbes that live in these environments become increasingly important in terms of bioprospecting for natural products from which new drugs can be made. This research is theoretical in nature and designed to guide the discovery of such micro-organisms by calculating "tipping points" (i.e., temperature, pressure, and compositional conditions that trigger the most dramatic changes in mineral reactions and/or fluid evolution). The focus of the work is on known hydrothermal vent systems from the Ridge 2000 Integrated Study Sites where extensive hydrothermal vent fluid compositions and mineral data are present. Goals of the project are to use thermodynamic constraints and calculations to predict the supply of chemical energy to microbial communities that inhabit seafloor hydrothermal vents. It will also focus on adding estimates of hundreds of additional organic compounds to thermodynamic databases to allow more complete and realistic calculations of organic transformations and the abiotic synthesis of organic compounds. Calculations will examine the full compositional ranges of igneous basement rocks and sediments that exist in mid-ocean ridge settings. By focusing on locating and understanding tipping points, the proposed work departs from most previous theoretical work, and provides a new way of looking at the evolution of hydrothermal systems and identifying the best locations to sample for high temperature or other unique microbial life forms. Broader impacts of the work include student training, building infrastructure for science in terms of providing much needed thermodynamic data for organic compounds, and public outreach.

Combining geochemical data with microbial ecological data makes it possible to predict the distribution of microbial populations and the processes that they catalyze in nature. In this research we will focus on the contrasting microbial processes of methane production (e.g., methanogenesis) and methane consumption (e.g., methanotrophy) as a framework for evaluating the linkages between geochemical predictions and the distribution, diversity, and activity of organisms that catalyze these processes. The overarching rationale for targeting these biological processes is that the combined activities of methanogenesis and methanotrophy largely control the flux of the potent greenhouse gas methane to our atmosphere, the extent of which may significantly impact global climate. Defining the constraints on the distribution of microbial populations catalyzing these two processes in nature can significantly advance our understanding of the impact that a perturbation to their environment would have on their respective activities and the consequence that this may have on the global carbon cycle. Existing geochemical predictions from hydrothermal ecosystems in Yellowstone National Park, Wyoming indicate that the occurrence of populations catalyzing methane production should be highly proscribed, but that aerobic and anaerobic methanotrophy should be widespread and that populations engaged in these activities should display significant genetic diversity as a function of the spring fluid composition. The thermodynamic predictions will be used to guide experiments aimed to interpret data on the distribution of methanogens and methanotrophs and their respective activities. The integration of geochemical data and biological data will be achieved using newly developed ecological modeling tools. These models will provide a more comprehensive understanding of the extent to which the distribution, diversity, and activity of functional groups of microorganisms reflect the physical and chemical characteristics of their environment. Defining the extent to which such relationships exist using this framework has critical implications for our understanding of the constraints which led to extant biodiversity and will enable predictions of how changes in environmental conditions will affect the functioning of those microbial ecosystems.
This unified research goal will engage students in hands on interdisciplinary research where they will merge the traditionally independent disciplines of geochemistry and microbial ecology. This goal will be met through the coordination of geochemical and microbiological analyses in field research settings as well as through coordinated laboratory experimentation at both Arizona State University and Montana State University. In addition, workshops will be held with the specific focus of training students in merging knowledge from these disciplines. Given this exciting area of scientific exploration and discovery, the proposed work will also result in several tangible opportunities for education and outreach, most of which are built on our previous experience and commitment to educational programs for various audiences. This includes field-and classroom-based efforts aimed at advancing scientific knowledge to other sectors of the public including K-12 students, undergraduate and graduate students, and high school and community college educators. This project also will help promote research on the geochemistry, energetics, and microbial ecology of terrestrial hot springs and active serpentinizing systems through networking among scientists worldwide.

Fluids circulating through the seafloor at seamounts, continental shelves, mid-ocean ridges, and elsewhere contain dissolved organic compounds that, during the course of their transit through the ocean crust, are exposed to elevated temperature-pressure environments where they are transformed into other organic molecules. These organics not only feed microbes in the deep biosphere but their reactions with minerals change them into other organic molecules. Such similar reactions and transformations that happened in the ocean crust back during the earliest days of our planet are likely to have played a major role in the formation of the essential organic components that resulted in life on Earth. This research carries out a series of high temperature and pressure experiments (200 to 350 C and 70 to 100 MPa, respectively) in which well-characterized, dissolved, isotopically-labelled, aqueous organic and chiral compounds are reacted with a variety of common seafloor hydrothermal oxide and sulfide minerals to examine the resulting changes in organic compounds and their rates of transformation. Transformations and rates of reaction will be examined both as a function of temperature and pressure as well as a function of the catalytic properties of the minerals in terms of surface area, charge distribution, and semi-conductor properties. Resulting data will be used to determine fundamental thermodynamic and kinetic parameters that can be used to make and test predictions and examine the implications of water-rock interaction and mineral catalysis as they apply to the development of organic molecules in the ocean crust. Experiments mimicking seafloor hydrothermal systems will be run as a function of pH, ionic strength, and redox state. Both hydrothermal gold bag (Dixon bomb) and static gold capsule experimental apparatuses will be used. Experiments will be designed using aqueous speciation modeling codes (e.g., SUPCRT and EQ3/6). Organic solutes, mineral reactants and products, and dissolved gases from the static and gold bag experiments will be analyzed by high precision gas chromatography and gas chromatographic mass spectrometry. X-ray diffraction, scanning electron microscopy, and scanning transmission electron microscopy. Preliminary experiments have already demonstrated proof of concept in terms of experiments being successful and yielding interpretable results. Broader impacts of the research include significant integration of research and education by using the research to transform how undergraduate geochemistry, organic chemistry, and astrobiology students are taught at Arizona State University. Research will be incorporated into courses and a series of podcasts and videos on themes relating to submarine hydrothermal systems and hydrothermal organic geochemistry will be developed as part of course offerings. These will then be improved through student crowd sourcing and posted for public consumption on the Internet. Results of the project will be applicable broadly across the academic sector into the fields of chemistry and hydrology as well as geothermal and materials science. The fundamental thermodynamic parameters and rate constants to be derived will have a potentially large impact in the chemical and petroleum engineering industrial sectors.

This project involves an interdisciplinary study of hydration, carbonation and oxidation of mantle peridotite interacting with aqueous fluids at temperatures below ~ 300C. The PIs will combine observations of outcrops and boreholes, geochemical analyses, structural measurements, geomechanical experiments and numerical modeling to investigate feedback between alteration and fluid transport, and to quantify the resulting geochemical fluxes. Field observations and sampling will take place mainly in the Samail ophiolite of Oman, where peridotite has undergone spreading-ridge-related hydrothermal alteration, hydration and carbonation in the hanging-wall of the subduction zone that emplaced the ophiolite over metasediments, and subaerial weathering. The PIs project will provide matching funds and results that dovetail with the 2015-2018 International Continental Scientific Drilling Program (ICDP) Oman Drilling Project, and the many other related efforts just getting underway. The PIs will continue their independently supported research on subduction zone alteration of mantle wedge peridotites at a range of pressures and temperatures, and work closely with other groups investigating seafloor and subduction-related peridotite alteration, in order to quantify the similarities and differences in alteration processes in these different tectonic environments. They will generalize their results to global alteration processes and geochemical cycles.

Alteration of peridotite is an essential process in Earth dynamics. Hydration of oceanic crust and mantle, followed by subduction, supplies water to drive arc volcanism, and modulates the hydrogen content of the mantle over time. Carbonate formation during alteration of peridotite, near the surface and in the hanging wall in subduction zones, is an important but poorly characterized link in the carbon cycle. Oxidation of minerals and concomitant reduction of fluids produces H2 and hydrocarbons, and a niche for chemosynthetic microbes. Chemical weathering is as important as magmatism and plate tectonics in shaping the Earths surface. The interplay of chemical and physical mechanisms of peridotite alteration is not well understood, but will be transformed as a result of emerging understanding of equilibria and kinetics in peridotite alteration, and reaction-driven cracking that has left us poised on the brink of a breakthrough at this little-studied frontier. The PIs will take advantage of low temperature, near surface, active peridotite alteration in Oman to study inputs, outputs, and the reaction zone in situ. Such a study is more difficult in smaller peridotite exposures with limited outcrop and more rainfall, nearly impossible in submarine hydrothermal systems, and completely impossible in studies of ancient systems. Such a comprehensive approach via 250 to 600 meter boreholes is very rare, if not unprecedented.

The objective of this project is to identify the reasons why microorganisms can live where they live. The focus is on identifying livable conditions in the environment, with the goal of explaining how temperatures and geochemical compositions combine to allow and support microbial life. Two things have to be true for an environment to be habitable: there have to be sources of energy, and those sources of energy have to persist long enough for life to take advantage of them. Things that burst into flame are not good to eat. Habitability can be quantified by combining methods to calculate the amounts of chemical energy available to microbes with measurements of the rates that resulting reactions happen with and without microbes present. The importance of this approach is that it can be used in diverse environments from soils to deep in the Earth's crust, allowing an expansion of scientific understanding of how our planet supports life, and even in biological systems including the human gut where there could be surprising applications to improve human health. In this study, environments that support microbes that use iron reactions as their source of energy will be studied including hot springs, acid mine drainage, and cold springs fed by snowmelt. By examining the same processes across diverse environments, this case study of the microbial iron cycle will serve as a template for future studies of other chemical energy sources. Ultimately these efforts will allow researchers to explain underlying reasons for the immense microbial diversity found on Earth.

Two things have to be true for microbes to gain chemical energy from the environment. First, there must be a source of energy. This requires the presence of compounds in differing oxidation states that are out of thermodynamic equilibrium with one another. Second, there must be mechanistic difficulties that are keeping those compounds from reacting, which means that the chemical energy cannot dissipate by itself. Using this energetic reference frame, geochemical habitability can be defined and quantified by the combined presence of thermodynamic and kinetic limitations at diverse environments on and in the Earth. As an example, microorganisms across the phylogenetic tree of life gain energy by reacting dissolved reduced iron with oxygen in environments ranging in temperature from freezing to boiling and pH values between 2 and 7. However, not all combinations of pH and temperature are habitable. In high-pH environments this reaction occurs rapidly on its own, which prevents microorganisms from using it, and the pH where this kinetic barrier occurs decreases with increasing temperature. In acidic environments, however, the abiotic oxidation reaction rate is significantly slowed, allowing microorganisms to catalyze iron oxidation and conserve some of the energy released. However, increasing acidity lowers the energy yield, ultimately creating an energy boundary to habitability at the lowest values of pH. Combining such energetic and kinetic boundaries permits habitability to be mapped for individual reactions using geochemical variables that include pH, temperature, and concentrations of reactants and products of the reaction. It is a goal of this research to generate habitability maps for the case study of iron oxidation and reduction reactions. Geochemical data from fieldwork at hot springs, acid mine drainage, and cold springs fed by snowmelt will be used to calculate energy supplies. Field experiments of biotic and abiotic rates of iron oxidation and reduction will determine kinetic limitations. Complementary lab experiments will provide abiotic rates. Molecular analyses will reveal the microbes likely to be responsible for driving the biological iron redox cycle in these environments. The resulting multi-dimensional habitability maps for several iron oxidation and reduction reactions will provide a framework for future studies of many other chemolithotrophic metabolic process throughout surface and subsurface environments on Earth, which will quantitatively constrain the discussion of habitability on other planets.

Earth scientists seek to understand the mechanisms of planetary evolution from a process perspective in order to promote the progress of science. They model the chemistry of melting of the interiors of planets as a result of heat flow within the body. They calculate the flows of energy and mass from the interior to the surface. They model the interaction of fluids and rocks, which drives chemical weathering and the formation of ore deposits. They seek to understand the synthesis and stabilities of organic compounds and their economic and biological roles. They study the interactions of atmosphere, oceans, biosphere and land as a dynamically coupled evolving chemical system. To achieve this level of understanding of planetary evolution, Earth scientists use software tools that encode two fundamentally different types of models: (1) thermodynamic models of naturally occurring materials, and (2) models of transport that track physical flows of both fluids and solids. Much of the fundamental science of planetary evolution lies in understanding coupled thermodynamic and transport models. This grant funds development of a software infrastructure that supports this coupled modeling of the chemical evolution of planetary bodies. It is their aim to establish an essential and active community resource that will engage a large number of researchers, especially early career scientists, in the exercise of model building and customization.

This is a project to create ENKI, a collaborative model configuration and testing portal that will transform research and education in the fields of geochemistry, petrology and geophysics. ENKI will provide software tools in computational thermodynamics and fluid dynamics. It will support development and access to thermochemical models of Earth materials, and establish a standard infrastructure of web services and libraries that permit these models to be integrated into fluid dynamical transport codes. This infrastructure will allow scientific questions to be answered by quantitative simulations that are presently difficult to impossible because of the lack of interoperable software frameworks. ENKI, via the adoption of state-of-the-art model interfacing (OpenMI) and deployment environments (HubZero), will modernize how thermodynamic and fluid dynamic models are used by the Earth science community in five fundamental ways: (1) provenance tracking will enable automatic documentation of model development and execution workflows, (2) new tools will assist users in updating thermochemical models as new data become available, with the ability to merge these data and models into existing repositories and frameworks, (3) automated code generation will eliminate the need for users to manually code web services and library modules, (4) visualization tools and standard test suites will facilitate validation of model outcomes against observational data, (5) collaborative groups will be able to share and archive models and modeling workflows with associated provenance for publication. With these tools we seek to transform the large community of model users, who currently depend on a small group of dedicated and experienced researchers for model development and maintenance, into an empowered ensemble of model developers who take ownership of the process and bring their own expertise, intuition and perspective to shaping the software tools they use in daily research. ENKI development will be community driven. Participation of a dedicated and diverse group of early career professionals will guide us in user interface development - insuring portal capabilities are responsive to user needs, and in development of a rich set of documentation, tutorials and examples. All software associated with this project will be released as open source.

Has Recent Tectono-Magmatic Activity at Lōʻihi (Kamaʻehuakanaloa) Seamount perturbed vent-fluid circulation and hydrothermal Fe export to the ocean?


Like volcanoes on land, submarine volcanoes are not continuously erupting but can remain dormant for long periods. Even while dormant, however, the magmatic heat present beneath a volcano’s surface can continue to drive hot springs in between eruptions. The focus of this study is hot springs at the Kamaʻehuakanaloa underwater volcano (previously known as Lōʻihi), situated about 30 miles south of the Big Island of Hawai’i which last erupted in 1996. Prior studies between the mid 2000’s and late 2010’s have shown that the multiple hot-springs associated with that last eruption, at the summit of the volcano have been cooling down continuously. This study will investigate whether two sets of recent earthquakes at Kamaʻehuakanaloa may have altered that cooling trend. In May 2020 earthquakes associated with magma intrusion into the chamber deep within the seamount were detected. In 1996 earthquakes similar to this accompanied a volcanic eruption. More recently still, in December 2021 the strongest earthquakes of any kind since the 1996 eruption were detected. This project will use a deep-diving robot to investigate whether lava was erupted on the seafloor during these earthquakes and also if the composition of the fluids (chemically altered seawater) flowing out of the seafloor at the volcano’s summit has changed.


The Lōʻihi seamount (recently renamed Kamaʻehuakanaloa) last erupted in 1996, significantly reshaping its summit and creating three collapse pits. Inside one of these, Pele’s Pit, hot springs have been studied which exhibited temperatures in excess of 200°C immediately post-eruption. Since 2006, however, the multiple sites that have been subject to long-term study within Pele’s Pit and around its rim have shown more modest temperatures of 15-55°C which, further, have exhibited progressive cooling at a rate of 1-2°C over a 12-year period from 2006 to 2018 (the most recent year for which time-series data exist). Thermodynamic modeling of the fluids collected in 2018 has provided new insight that the subsurface hydrothermal circulation within this steep sided seamount may extend much deeper than is typical at mid-ocean ridges (which are more elongate and exhibit shallower-sloping ridge flanks). Further, a geochemical consequence of Lōʻihi’s unusual circulation pattern may account for the unusually Fe-rich nature of the vent-fluids emerging from the seafloor at this intra-plate setting, and their impact on the surrounding ocean, when compared to mid-ocean ridges vents. This project will extend the 2006-2018 time-series of vent studies at Lōʻihi to investigate whether the subsurface hydrothermal circulation system has been perturbed by two significant episodes of seismicity that have subsequently occurred, as detected by the US Geological Survey’s Hawai’i Volcano Observatory. In May 2020, a swarm of earthquakes was detected that were distinctive compared to all seismic activity since the volcano last erupted in May 1996 because they exhibited T-phase activity, recognized as being diagnostic of magmatic fluids migrating within the interior of the seamount and potentially indicative of magma replenishment. In December 2021, an even more pronounced episode of seismicity was detected, up to magnitude M4.9, which matched the strongest earthquakes detected during the 1996 eruptions. This project will use the ROV Jason to investigate whether the seafloor hydrothermal venting at Lōʻihi has been perturbed following these episodes of seismicity. The project will test the hypothesis that the earthquakes, detected by T-phase seismic signals, perturbed the deep hydrothermal circulation cell at Lōʻihi, which in turn should be detectable at the seafloor through changes in vent-fluid temperatures and geochemical compositions. Changes in seafloor morphology and locations of vent-sites compared to the previous ROV dives in 2018 may also be expected. Conversely, the null hypothesis would be that the vent-sites that have been studied since 2006 continue to cool progressively (each vent should then be 6±2°C cooler than when last studied in 2018) with compositions that will have changed accordingly. Importantly, proving this null hypothesis would still be scientifically valuable. It would extend the longest time series available for any intra-plate hydrothermal field worldwide and continue to collect pre-event data in anticipation of future extrusive volcanism at Lōʻihi that will occur.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.